This invention relates generally to slide fasteners, and in particular to a method of attaching a slider to a fastener chain after the same is secured to the edges of an opening in a garment or like article. The invention is also specifically directed to a slider holder adapted for use with such method.
It is now widely practised among the manufacturers of ready-made garments and other articles to cut an elongate slide fastener chain (by which are meant a pair of tapes carrying longitudinal rows of fastener elements along the opposed inside edges thereof) into lengths determined in accordance with the shape and size of the articles and to sew or otherwise secure such required lengths of the fastener chain to the successive articles. Other parts of the slide fasteners, such as top and bottom stops as well as sliders, are attached after the fastener chain is secured to the articles. It has been found that this practice results in a great saving in the manufacturing costs of such articles.
However, this practice has its own disadvantage with regard to the manipulation of the fastener stringers, which have been secured to the edges of a desired article as aforesaid, through the guide channels in the slider so as to cause the rows of fastener elements on their opposed inside edges to interlock properly in their correct relative positions. It requires the highest degree of dexterity and mental concentration on the part of the workers to manually thread the two fastener stringers simultaneously through the slider without causing misalignment between the interfitting rows of fastener elements. For this reason the assembly operation of the slide fasteners according to the above described practice has been highly retarded.
In order to overcome the foregoing disadvantage of the prior art, some manufacturers have more recently resorted to the use of fastener elements capable of elastic deformation. Such fastener elements are formed of synthetic resin monofilaments, such as those of polyamide or polyester, and are either coiled or zigzagged in shape. In the use of these known fastener elements, the fastener stringers secured to an article are manipulated through the guide channels in the slider one after the other. The resultantly interlocked rows of fastener elements in wrong relative positions are then manually separated from each other so that the fastener elements are still held interlocked only at their portions within the slider which is now located at one extremity of the fastener stringers.
Thereafter, in order to readjust the relative positions of the misfitting fastener elements, one of the stringers is forcibly pulled through the slider by taking advantage of the elastic deformation of the fastener elements. Following this operation it is necessary that the two fastener stringers be pulled in a fastener closing direction through the slider so that the latter will be positioned at or adjacent that point on the stringers where a bottom stop is to be affixed. This bottom stop is secured to the required point after pulling the fastener stringers back again through the slider in a fastener closing direction. This latter method is currently preferred because it facilitates the assembly operation of the slide fasteners, without requiring undue attention to the correct alignment of the fastener elements.
A special problem has arisen in connection with the second described method, however, in that the fastener elements are frequently caught in the guide channels in the slider as the fastener stringers are pulled therethrough in a fastener opening direction following the readjustment of the relative positions of the misfitting fastener elements. If only this problem is overcome, it is certain that the assembly operation of the slide fasteners according to this second method will be still more expedited.
As a result of extensive search for the possible causes of the above noted problem, it has now been discovered that since the slider is held horizontally during the assembly operation in accordance with the prior art, the fastener elements on the inside edges of the stringers stand up, so to say, as the stringers are caused to make a sharp turn from their vertical to horizontal position to be fed into the guide channels in the slider. Moreover, because the fastener stringers are already secured to an article as above stated, they are inevitably held vertically due to the added weight of the article. This is all the more reason why the free ends of the fastener elements rise and get caught in the slider guide channels.